Method to control a steering system of a motor vehicle with an increase in supply voltage to an actuator motor after unilateral failure of a redundant system or in case of extreme loads or short-term performance requirements

Abstract

A method to control a steering system of a road vehicle, the steering system including an actuator with at least two redundant power packs, the method including detecting a failure and/or degradation in or of the at least two redundant power packs of the actuator and/or switching off a malfunctioning one of the at least two redundant power packs, or detecting extreme loads or short-term performance requirements; and increasing a supply voltage for at least one functioning power pack of the actuator to a value higher than a supply voltage under normal conditions to provide a higher power output of the actuator than power output under normal conditions.

What is claimed is: 
     
         1 . A method to control a steering system of a road vehicle, the steering system including an actuator with at least two redundant power packs, the method comprising:
 a) detecting a failure and/or a degradation in or of one of the at least two redundant power packs of the actuator and/or switching off a malfunctioning one of the at least two redundant power packs; or   detecting extreme loads or short-term performance requirements; and   b) increasing a supply voltage for at least a functioning one of the at least two redundant power packs of the actuator to a value higher than a supply voltage under normal conditions to provide a higher power output of the actuator than a power output under normal conditions.   
     
     
         2 . The method according to  claim 1 , wherein the actuator is a road wheel actuator or a feedback actuator of a steer-by-wire steering system or an actuator of an electric power assisted steering system, which provides an assistance torque. 
     
     
         3 . The method according to  claim 1 , wherein the road vehicle is an electric vehicle, and in step b), a voltage converter is used to increase the supply voltage. 
     
     
         4 . The method according to  claim 1 , wherein the road vehicle includes an internal combustion engine, and in step b), the increase in the supply voltage is generator controlled. 
     
     
         5 . A steering system for a road vehicle configured to perform the method according to  claim 1 .